XPCS at the APS: Implementation and Operations

Alec Sandy

X-Ray Science Division

Argonne National Laboratory

2

Acknowledgements

Sector Staff

– Suresh Narayanan

– Michael Sprung

TRR Group Leader

– Jin Wang

Former CAT members and continuing active partners:

– Larry Lurio

– Simon Mochrie

– Mark Sutton

3

Outline

Background

Mission

Implementation

Scientific and General User Program

Opportunities for Improvement (at NSLS-II)

Challenges

4

Background

Sector 8-ID

– ≤ 2002 IMM-CAT• IBM, McGill and MIT• Multiple experiment capabilities promised in PDR but not delivered

because of costs and dwindling PI participation – Beamline specialization a hidden benefit

– One of first 3 CAT’s designated by DOE for transition to APS operational responsibility

– 2003–current• Transition to APS XOR operations completed

– IMMY/XOR CAT → XOR 8-ID– Beamline staffed with APS personnel within the Time Resolved

Research Group– Beamtime allocated via APS General/Partner User system– Capital and operational funds via APS

5

Mission

Beamline Mission

– Develop and apply X-Ray Photon Correlation Spectroscopy (XPCS) to the study of equilibrium and non-equilibrium dynamics in condensed matter

• Small Q XPCS (Station 8-ID-I)• (Limited) Large Q XPCS, liquid surface XPCS (Station 8-ID-E)

– Currently, one of 2 such facilities in the world

– Develop and apply Grazing Incidence Small-Angle X-Ray Scattering (GISAXS) to study the structure and ordering kinetics of thin films (8-ID-E)

– “High-end” SAXS (Station 8-ID-I)

– Coherent diffraction imaging (Station 8-ID-I)

6

Implementation

Beamline 8-ID is a minimalist undulator beamline

– Minimal optics for coherence preservation

– Minimal diagnostics because of legacy cost considerations

– First and second optics enclosures: 8-ID-A and 8-ID-D

– Experiment stations: 8-ID-E and 8-ID-I Primary features

– Simultaneous experiment operations in 8-ID-E and 8-ID-I via beam-splitting monochromator in 8-ID-D

– Pinhole and mirror in 8-ID-A to reduce downstream power load

Undulator A

8-ID-A FOE

8-ID-D

8-ID-E

8-ID-IMono or Pink beam

0 m

30 m51 m

65 m

GISAXS

Small-angle XPCS

Mono beam

“G”“E”

large Q XPCS

7

Implementation

8-ID (ongoing) design requirements

– Preserve delivered coherence

– Provide extremely stable and reproducible coherent x-ray beam to experimenters

– (Fully utilize delivered coherence)

Requirements achieved by

– Minimizing number of optical components

– Minimizing power loading

– (Implementing vertical focusing)

8

Implementation

Radiation Source

– High beta straight section

– 1-σ source sizes (σ) 270 m (H) × 9 m (V)

– 1× Undulator A (72-pole by 3.3 cm = 2.4 m device in 5 m straight) Transverse Coherence Lengths

– ξ = λR/(2πσ) → 7 m (H) × 200 m (V)

– Low-beta [σ = 120 m (H)] operations possible and will be examined during upcoming operations cycles

5 m straight section allows tandem undulator in the future

2X Undulator

8-ID-A FOE

8-ID-D

8-ID-E

8-ID-IMono or Pink beam

0 m

30 m51 m

65 m GISAXS,large Q XPCS

Small-angle XPCS

Monobeam

9

Implementation

First Optics Enclosure 8-ID-A

– Windowless connection to APS front end• Used by 40% of APS ID beamlines with no operational issues over

past 10 years• Preserves beam brilliance

PINHOLE APERTURE and DIFFERENTIAL PUMP

– Pinhole aperture• 300 m exit diameter tapered

pinhole greatly reduces transmitted power without sacrificing useful coherent flux– Incident power 1600 watts,

transmitted power 5–10 watts (typ.)

– Enables small, water-cooled optical components farther downstream

10

Implementation

First Optics Enclosure 8-ID-A

– Horizontally-deflecting 12-cm-long side bounce mirror• Currently most problematic component in the beamline with

respect to preserving the source• Small size allows “cheap” replacement as optics fabrication

capabilities improve

11

Implementation

Secondary Optics Enclosure – 8-ID-D

– Horizontal, single-bounce ESRF-designed and -built monochromator

• Effectively fixed energy operation: 7.35 keV• New crystal holder to eliminate vacuum-water connection

allowing eventual removal of upstream Be window• Increased stability and brilliance via better cooling and new

connections to 8-ID-E experiment set-ups

PINK BEAM TO I STATION (XPCS)

MONOCHROMATIC BEAM TO E STATION (GISAXS)

Si(111) or Si(220)

PINK BEAM FROM FOE

“E” Si(220)“G” Si(111)

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Implementation

Experiment Station 8-ID-E

– GISAXS dominates user program

– Large Q XPCS and liquid surface XPCS

• Require additional user support

Courtesy Oleg Shpyrko, UCSD

Large Q XPCS

Liquid Surface XPCS

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Implementation

Experiment station 8-ID-I

– Transmission XPCS

– Viscous surface XPCS

– SAXS

– CXDI

Brilliance-preserving monochromator*

Measured stability increases Optical contrast doubled per 2003 values

Re-engineered SAXS set-up

*S. Narayanan et al., J. Synchrotron Rad. 15, 12 (2008)

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Scientific and General User Program

Many recent high-impact XPCS results obtained at 8-ID

O. G. Shpyrko, E. D. Isaacs, J. M. Logan, Yejun Feng, G. Aeppli, R. Jaramillo, H. C. Kim, T. F. Rosenbaum, P. Zschack, M. Sprung, S. Narayanan, and A. R. Sandy; "Direct measurement of antiferromagnetic domain fluctuations," Nature 447, 68

B. Chung, S. Ramakrishnan, R. Bandyopadhyay, D. Liang, C.F. Zukoski, J.L. Harden, R.L. Leheny, "Microscopic Dynamics of Recovery in Sheared Depletion Gels," Phys. Rev. Lett. 96 (22)

F. Livet, F. Bley, F. Ehrburger-Dolle, I. Morfin, E. Geissler, M. Sutton, "X-ray intensity fluctuation spectroscopy by heterodyne detection," J. Synchrotron Rad. 13 (6), 453-458 (2006).

15

Scientific and General User Program

From last 8-ID sector review (9/2006):“…. I was personally well aware of the very positive direction for Sector 8, but it is particularly nice to have it externally recognized, and especially to hear the scientific impact so highly valued. ….”

Murray (Gibson, ALD Director)

Respectable XPCS-specific publication rate – the majority of which are published in high-impact factor (impact factor ≥ 5) journals

0

1

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8

9

10

Nu

mb

er2004 2005 2006 2007

Year

8-ID XPCS Publications

Journal publication

High-impact journal publication

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Scientific and General User Program

80% of beamtime now allocated through the APS program

– Concomitant increase in GU publications

0

1

2

3

4

5

6

7

8

9

10

Nu

mb

er

2004 2005 2006 2007Year

8-ID XPCS Publications

CAT publication

General user publication

For CY 2007, 8-ID XPCS-time allocated/used as follows:

XPCS Experiment Type Allocation

Small-Q Transmission 63%

Small-Q Liquid Surface 3%

Small-Q Viscous Surface 27%

Large-Q 7%

(infrastructure and/or FTE-limited)

(infrastructure and/or FTE-limited)

17

Scientific and General User Program

8-ID regular and semi-regular General Users (GU’s)– Italics indicate new GU’s since 2003-APS XOR Operations

PI Institution PI Institution

Prof. L. Lurio NIU Prof. S. Mochrie Yale

Prof. M. Sutton McGill University Prof. N. Balsara UC-Berkeley

Prof. M. Foster U. Akron Prof. A. Dhinojwala U. Akron

Prof. S. Sinha UC-San Diego Prof. R. Leheny Johns Hopkins

Prof. J. Harden U. of Ottawa Prof. O. Shpyrko UC-San Diego

Dr. J. Lal ANL Prof. S. Chen MIT

Prof. T. Lodge U. Minnesota Prof. M. Mackay Michigan State

Dr. Steve Dierker BNL Prof. K. Ludwig Boston U.

Dr. C. Gutt HASYLAB Prof. W. Burghardt Northwestern

Dr. P. Thiyagarajan ANL Prof. J. Basu Indian Institute of Science

Prof. H. Kim Sogang University (Korea)

Prof. C. Co University of Cincinnati

Prof. C. Zukoski UIUC

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Scientific and General User Program

For CY2007, XPCS experiment outcomes were roughly as follows:

Outcome Fraction

Completed Successfully 24%

Ongoing – Partially Successful 63%

Unsuccessful – Beamline Problems 3%

Unsuccessful – Sample Radiation Damage 7%

Unsuccessful – Other Sample Issues 3%

Estimate that (partially) successful experiments run, on average, ~ 3–4 cycles at 18 shifts per cycle before “complete”

Current over-subscription rate for 8-ID is ~ 40%

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Scientific and General User Program

8-ID, via simultaneous experiment station operations, supports nearly a full end-station complement of XPCS experiments as well as supporting several additional unique experiment capabilities (for various reasons)

Technique “End-Station” Allocation

XPCS 70%

GISAXS 70%

“High-end” SAXS 15%

CXDI 15%

Total 170%

CCD

InjectorslitChamber

Scattered x-ray beam

0.5-m-diam injector

CCD

InjectorslitInjectorslitslitChamber

Scattered x-ray beam

0.5-m-diam injector

0.1

1

10

100

Inte

nsity

[cm

-1]

5 6 7 80.01

2 3 4 5 6 7

Q [A-1

]

Experimental Intensity

Model calculated Intensity

4sin/ (Å-1)

0.1

1

10

100

Inte

nsity

[cm

-1]

5 6 7 80.01

2 3 4 5 6 7

Q [A-1

]

Experimental Intensity

Model calculated Intensity

4sin/ (Å-1)

CXDI from de-alloyed AgAu particlePartial reconstruction

(X. Xiao and Q. Shen, ANL)

TR-SAXS from supercritical condensates(S. Lin and C. Carter, WPAFB)

20

Scientific and General User Program

Despite simultaneous station operations, several intimately and peripherally related programs remain under-developed at 8-ID because of lack of:

– Beamtime

– FTE’s

– Infrastructure

Under-developed coherence-related programs at 8-ID include

– Large Q XPCS

– Liquid surface XPCS

– Hard x-ray coherent x-ray diffraction imaging (CXDI)

Transmission small-angle XPCS could grow significantly as well

– Aggressive outreach efforts are limited by the lack of available beamtime

There remains significant room for growth in the field of XPCS!

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Opportunities for Improvement

Despite ubiquitous XPCS phase diagram to the contrary, XPCS experiments to-date have been restricted to lower left corner of theoretically accessible phase space

*Graphic courtesy of A. Robert, SLAC

*

Access to larger wave-vector transfers and/or higher frequencies requires brighter sources like NSLS-II and better utilization of the coherent flux delivered by 3rd generation sources

22

Opportunities for Improvement

XPCS “tomorrow”XPCS today

Today, in order to remain in the diffraction limit, only 10% of the coherent flux delivered by the undulator is used for 8-ID XPCS experiments

– The vertical coherence length is too large

Brilliance-preserving vertical focusing allows the vertical coherence length to be tailored so that the entire coherent flux can be used

– XPCS signal-to-noise ratio considerations show that 100× faster dynamics or 10× weaker scatterers can be studied

23

Opportunities for Improvement

Vertical focusing at NSLS-II can be effectively implemented via kinoform lenses

Sample

K. Evans-Lutterodt et al., Opt. Express 11, 919 (2003)

Currently examining lens with the following properties:

•Efficiency 50% at 7. 35 keV

•1-σ focal line width = 0.9 m (0.8 m ideal)

•1.04 m focal length (0.97 m ideal)

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Opportunities for ImprovementQ

y (n

m-1

)27 m × 20 m (V×H)

unfocused200 m × 20 m (V×H)

unfocused200 m × 20 m (V×H)

focused

×1 ×0.1 ×0.2Q x (nm-1 )

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Opportunities for Improvement

))()(()()(),( 212121 rIrIrIrIrrC

Qy (

nm

-1)

27 m × 20 m (V×H) unfocused

Q x (nm-1 )

200 m × 20 m (V×H) unfocused

200 m × 20 m (V×H) focused

Spatial Autocorrelation:

26

Opportunities for Improvement

End station design needs to be included in the beamline design process

Number and best type of staffing for beamlines needs to be considered carefully

– At APS 3 beamline scientists and 0.5 of a scientific associate support 2 simultaneously operating beamlines at 8-ID

• Many recent GU’s have very little scattering background• Increased staffing is an obvious remedy but serious thought should

be given to the type of staff especially with more specialized “static” beamlines– Operations manager per ESRF– Beamline scientists provide more strategic support and user

recruitment per neutron facilities– Scientific associates– Scientific computing support

27

Challenges

Competition for both quality GU’s and quality beamline staff from nascent 3rd and 4th generation XPCS facilities and existing 3rd generation facilities

– SLS, Diamond, Petra-III• Enhanced brightness and/or sophisticated

detector programs

– LCLS and XFEL• Different kettle of fish

– APS and ESRF• Fully operational with significant upgrade

plans/possibilities

Detectors!

– Powerful detectors are needed to effectively utilize increased coherent flux

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8-ID Help Wanted